A Universal Turing Machine In 100 Punchcards

New submitter theclockworkcomputer writes "100 years ago tomorrow, Alan Turing was born. To celebrate, I wrote a Universal Turing Machine in 100 Punchcards. I've uploaded a video to explain a small part of the read head (the Jacquard). One needle is shown out of a total of 28. As this is about a program for a Turing Machine and not about a Turing Machine itself, I hope to be excused from the requirement of infinite tape."

Linear bounded automaton

[tepples]

But what is possible is a universal linear bounded automaton, and that's what physically realized Turing machines become.

Wow you couldn't even read the summary?

[Anonymous Coward]

This is not a universal Turing machine, since those things are impossible in this universe. Not even humans are universal Turing machines.

Right. And from excessively short summary:

As this is about a program for a Turing Machine and not about a Turing Machine itself, I hope to be excused from the requirement of infinite tape.

seems fair

[Thud457]

He provides the Turing Machine emulator, you provide the infinitely long tape.
Why exactly is program store considered to be an integral part of the definition? On all practical computers, that's an interchangeable external part.

Re:

[Immerman]

Probably because until quite recently most computers were single-purpose or hardware-programmable (i.e. you'd need to rewire it to do something different). An orerry, astrolabe, or pocket calculator are all examples of non-programmable computers - they perform useful computations, quite complex ones in the case of a high-quality orerry, but are inherently special-purpose. Turing's insight was that the operation of the machine could itself be controlled by input data, making it a general-purpose machine th

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[theclockworkcomputer]

A Turing Machine is comprised of a tape, a wheel, a read/write head and a control. The program on the website is merely the rule table inside the control. The Jacquard and some other parts of the clockwork computer [theclockworkcomputer.com], of which also a schematic exists [theclockworkcomputer.com] can be regarded as a the missing parts minus the tape. There is no actual tape, but the program thinks the memory of the computer is the tape and uses that. The memory has only 12 nibbles of storage, but at 12 punchcards per minute, it takes hours before it runs

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[itsdapead]

Right. And from excessively short summary:

As this is about a program for a Turing Machine and not about a Turing Machine itself, I hope to be excused from the requirement of infinite tape.

His finite Turing machine ran out of tape before he got that far. Those things really are bloody useless for web browsing.

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[K. S. Kyosuke]

This is not a universal Turing machine, since those things are impossible in this universe. Not even humans are universal Turing machines.

Unless you require a Turing machine to be infinitely fast, you will never be able to scan the whole physical tape, so an infinite virtual tape should be an adequate replacement, or did I get it wrong?

Re:Just to be pedantic

[tendays]

Indeed. Turing machines don't require infinite tapes, they require unbounded tapes. In particular the initial state of the tape must contain at most a finite number of non-blank cells. Working with a finite tape is therefore fine as long as you are ready to enlarge it when the head reaches the boundary (so that, to the machine, it appears infinite). In the same sense, a physical computer could act as a Turing machine if, when it runs out of memory, an operator could come and plug in an extra hard drive (and if memory addresses were made in a way that they can be arbitrarily large).

LEGO Turing machine

[wisebabo]

www.youtube.com/watch?v=cYw2ewoO6c4

I'm not sure if the plans are available anywhere but since (I think) it's built off a standard MindStorms LEGO set anyone should be able to recreate it.

I understand, however, that LEGO will be unable to provide an infinite number of bricks that are needed for full implementation.

Infinite Legos - Blame the Cheap Parents

[Dareth]

Nah, it is cheap parents who will not pay for them with their infinite incomes.

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[Em Adespoton]

That means one of the requirements should be a 3D printer... I seem to recall that someone made one out of LEGO.

irony of Alan's death

[peter303]

He was hounded into dangerous therapies because of his sexual orientation. Now the largest computer company in the world is run by a gay man. What would Alan had given us with another 20 years?

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[Anonymous Coward]

Please don't compare people who have actually done stuff like Alan Turing to management jobs that any idiot is qualified for.

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[samkass]

Whoosh... someone utterly misses the point.

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[Anonymous Coward]

Wait a minute ... Balmer's gay?

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[camperdave]

Wait a minute ... Balmer's gay?

Explains a lot, doesn't it?

Enough!

[elsurexiste]

Can the word "Turing" be mentioned in a Slashdot submission without some random guy bringing up his sexual orientation?

Everyone knows the story, it has been denounced and publicly acknowledged and an official "I'm sorry" was told. I welcomed those events and moved on. The meme, alas, persists. Even Simon Wiesenthal said something like "We can't pretend there weren't deaths in the holocaust, but we can't think about it all the time".

Now, can we talk about what's relevant? Like TFA?

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[tool462]

I thought his problems came about specifically because of his distaste for fannies...

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[dissy]

Now, can we talk about what's relevant? Like TFA?

You must be new here ;}

Realizing there is no chance anyone will read TFA, let alone discuss it, personally I would just be happy if the homophobes would crawl back under their rocks and let the important off topic discussions continue!

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[samkass]

He was hounded into dangerous therapies because of his sexual orientation. Now the largest computer company in the world is run by a gay man. What would Alan had given us with another 20 years?

One would hope nothing... didn't the guy deserve a lifelong vacation by that point?

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[Em Adespoton]

Hmm... did Turing really die, or was that a Dalek coverup?

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[DerekLyons]

What would Alan had given us with another 20 years?

Hard to tell. In his latter years, he went wandering off down all kinds of intellectual paths. He might have produced great things, he might have produced mediocre things, he might have produced nothing of use at all.

Bravo! Good Job!

[LifesABeach]

I would be very interested in how you made what you made.

Just Like on American Dad

[eldavojohn]

I would be very interested in how you made what you made.

I as well am very impressed and tip my hat in amazement. However, as I watched the video and then went to his page and started trying to understand how this would communicate with his mechanical bus, I couldn't help but wonder if he had consumed vast amounts of Cougar Boost [youtube.com].

No excuse.

[John Hasler]

Finite tape -> state machine.

schematic

[theclockworkcomputer]

For who is interested here is a schematic [theclockworkcomputer.com] of the machine

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[LifesABeach]

I saw the youtube site. My first thought was what software was used to make the "mechanical" visual. Possibly Blender3D?

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[theclockworkcomputer]

Hi. NX7.5 animation and motion (at work in the weekends). A 2001 version of Rhino to model and animate the leafs. Gimp to past the leafs into the animation. Inkscape to render the titles. Audacity to edit the sound. Blender to convert the stills to avi and add the sound.

How beautiful!

[Muad'Dave]

Wow. Regardless of the geek cred you get for making such a beast, let me commend you on the sheer artistic beauty of your website and the video. Just wow.

+1 cool

[Fubari]

I wish there was a way to add "Likes" to articles, this one deserves a +1 cool.